GB1587298A - Ethylation of toluene or ethylbenzene with high silica/alumina zeolite catalysts - Google Patents

Description

PATENT SPECIFICATION ( 11) 1 587 298

00 ( 21) Application No 21081/78 ( 22) Filed 22 May 1978 ( 19), e ( 31) Convention Application No 809510 ( 32) Filed 23 Jun 1977 in ( 33) United States of America (US) > ( 44) Complete Specification Published 1 Apr 1981

UJ ( 51) INT CL 3 CO 7 C 2/66 15/02 ( 52) Index at Acceptance C 5 E 227 242 385 CF 7 ( 54) ETHYLATION OF TOLUENE OR ETHYLBENZENE WITH HIGH SILICA/ALUMINA ZEOLITE CATALYSTS ( 71) We, MOBIL OIL CORPORATION, a Corporation organised under the laws of the State of New York, United States of America, of 150 East 42nd Street, New York, New York 10017, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 5

This invention relates to a process for producing ethyl toluene or diethylbenzene with minimal undesired by-product formation utilizing a specified crystalline aluminosilicate zeolite catalyst.

Alkylation of aromatic hydrocarbons utilizing crystalline aluminosilicate catalysts has heretofore been described U S 2,904,697 to Mattox refers to alkylation of aromatic 10 hydrocarbons with an olefin in the presence of a crystalline metallic aluminosilicate having uniform pore openings of about 6 to 15 Angstrom units U S 3,251,897 to Wise describes alkylation of aromatic hydrocarbons in the presence of X or Y-type crystalline aluminosilicate zeolites, specifically such type zeolites wherein the cation is rare earth and/or hydrogen U S 3,751,504 to Keown et al and U S 3,751,506 to Burress describe 15 vapor phase alkylation of aromatic hydrocarbons with olefins, e g benzene with ethylene, in the presence of a ZSM-5 type zeolite catalyst.

While the above-noted prior art is considered of interest in connection with the subject matter of the present invention, the toluene ethylation process described herein in which undesired by-products, including light gases such as methane, ethane, propane, propylene 20 and C 4 olefins and C 4 paraffins and unwanted aromatics such as benzene, ethylbenzene and xylenes are minimized utilizing a catalyst of a crystalline aluminosilicate zeolite having a constraint index of 1 to 12 and a silica/alumina mole ratio in excess of about 500 has not, insofar as is known, been heretofore described.

Ethyltoluene and diethylbenzene are valuable chemicals They are also subject to 25 dehydrogenation to produce vinyltoluene and divinylbenzene respectively It is evident that the presence of substantial quantities of unwanted light gases or other aromatics in the ethyltoluene or diethylbenzene product of interest is highly undesirable Some of the unwanted by-products, particularly those of aromatic configuration, have been difficult to separate from the desired ethyl-substituted product It has accordingly heretofore been 30 necessary to remove these unwanted by-products from the desired ethyltoluene or diethylbenzene product by expensive distillation techniques, especially in instances where said product is intended for subsequent dehydrogenation.

It is evident that the availability of ethyltoluene or diethylbenzene in which interfering by-products are absent or at least present in minimum amount would eliminate the 35 necessity for expensive prior removal of such products.

In accordance with the present invention, a process has been discovered for producing ethyltoluene or diethylbenzene containing minimal amounts of undesired byproducts, thus eliminating the heretofore necessary expensive purification procedures and loss of starting materials to undesired products Following the teachings of this invention, ethyltoluene and 40 diethylbenzene may be produced with only trace amount of unwanted other aromatics and light gaseous by-products.

According to this invention we provide a process for effecting ethylation of a monoalkyl benzene wherein the alkyl substituent contains 1 or 2 carbon atoms to yield a mixture of ethyl toluene or diethylbenzene isomers with minimal undesired by-product formation, 45 1 587 298 which comprises contacting said monoalkyl benzene with an ethylating agent, under conversion conditions, including a temperature between about 250 WC and about 600 C, a pressure between about 0 1 and about 100 atmospheres, utilizing a feed weight hourly space velocity between about 0 1 and about 1000, in the presence of a catalyst comprising a crystalline aluminosilicate zeolite characterized by a constraint index within the approxi 5 mate range of 1 to 12 and a silica to alumina mole ratio of at least about 500.

It has been found that the silica/alumina mole ratio is a critical parameter in achieving low production of unwanted by-products during the ethylation reaction Crystalline aluminosilicate zeolite catalysts heretofore employed in alkylation of aromatics have been characterized by a silica/alumina mole ratio of 300 or less Generally, such ratio has not exceeded 10 about 100 The use of these type crystalline aluminosilicate zeolite catalysts has led to the formation of considerable amounts of the aforementioned undesired byproducts, particularly under conditions of high temperature.

Ethylation, in accordance with the process described herein, is effectively accomplished at a temperature between about 250 and about 600 C, at a pressure of between about 0 1 15 and about 100 atmospheres utilizing a feed weight hourly space velocity (WHSV) between about 0 1 and about 1000 The latter WHSV is based upon the weight of catalyst composition, i e total weight of active catalyst and binder therefore The molar feed ratio of mono alkyl benzene ethylating agent is generally between about 1 and about 10.

The ethylating agent employed for effecting ethylation of toluene or ethylbenzene in 20 accordance with the present invention is generally ethylene or a gasesous mixture high in this reactant The latter may comprise refinery streams or other gaseous product mixtures of high ethylene content Other suitable ethylating agents include ethyl alcohol and ethyl halies, e g ethyl chloride; diethyl ether, diethyl sulfide and ethylmercaptan.

In accordance with the present invention, the above-described reactants are brought into 25 contact, under conversion conditions, suitable with a bed comprising particle form catalyst containing a crystalline aluminosilicate having a constraint index within the approximate range of 1 to 12 and a silica/alumina mole ratio of at least about 500 and which may be as high as 2000.

The zeolite catalysts utilized herein are members of a novel class of zeolites exhibiting 30 some unusual properties The zeolites induce profound transformation of aliphatic hydrocarbons to aromatic hydrocarbons in commercially desirable yields and are generally highly effective in conversion reactions involving aromatic hydrocarbons Although they have unusually low alumina contents, i e high silica to alumina ratios, they are very active even when the silica to alumina ratio exceeds 30 The activity is surprising since catalytic 35 activity is generally attributed to framework aluminum atoms and cations associated with these aluminum atoms This is especially surprising in the present instance since high activity was observed even with a silica/alumina ratio of 1600/1 These zeolites retain their crystallinity for long periods in spite of the presence of steam at high temperature which induces irreversible collapse of the framework of other zeolites, e g of the X and A type 40 Furthermore, carbonaceous deposits, when formed, may be removed by burning at higher than usual temperatures to restore activity In many environments the zeolites of this class exhibit very low coke forming capability, conducive to very long times on stream between burning regenerations.

An important characteristic of the crystal structure of this class of zeolites is that it 45 provides constrained access to, and egress from the intracrystalline free space by virtue of having a pore dimension greater than about 5 Angstroms and pore windows of about a size such as would be provided by 10-membered rings of oxygen atoms It is to be understood, of course, that these rings are those formed by the regular disposition of the tetrahedra making up the anionic framework of the crystalline aluminosilicate, the oxygen atoms 50 themselves being bonded to the silicon or aluminum atoms at the centers of the tetrahedra.

Briefly, the preferred type zeolites useful in this invention possess, in combination: a silica to alumina mole ratio of at least about 500 and a structure providing constrained access to the crystalline free space.

The silica to alumina ratio referred to may be determined by conventional analysis This 55 ratio is meant to represent, as closely as possible, the ratio in the rigid anionic framework of the zeolite crystal and to exclude aluminum in the binder or in cationic or other form within the channels Although zeolites with a silica to alumina ratio of at least 500 are useful, it is preferred to use zeolites having higher ratios of at least about 1000 Such zeolites, after activation, acquire an intracrystalline sorption capacity for normal hexane which is greater 60 than that for water, i e they exhibit "hydrophobic" properties It is believed that this hydrophobic character is advantageous in the present invention.

The type zeolites useful in this invention freely sorb normal hexane and have a pore dimension greater than about 5 Angstroms In addition, the structure must provide constrained access to larger molecules It is sometimes possible to judge from a known 65 3 1 587 298 3 crystal structure whether such constrained access exists For example, if the only pore windows in a crystal are formed by 8-membered rings of oxygen atoms, then access by molecules of larger cross-section than normal hexane is excluded and the zeolite is not of the desired type Windows of 10-membered rings are preferred, although, in some instances, excessive puckering or pore blockage may render these zeolites ineffective 5 Twleve-membered rings do not generally appear to offer sufficient constraint to produce the advantageous conversions, although puckered structures exist such as TMA offretite which is a known effective zeolite Also, structures can be conceived, due to pore blockage or other cause, that may be operative.

Rather than attempt to judge from crystal structure whether or not a zeolite possesses the 10 necessary constrained access, a simple determination of the "constraint index" may be made by passing continuously a mixture of an equal weight of normal hexane and 3-methylpentane over a small sample, approximately 1 gram or less, of catalyst at atmospheric pressure according to the following procedure A sample of the zeolite, in the form of pellets or extrudate, is crushed to a particle size about that of coarse sand and 15 mounted in a glass tube Prior to testing, the zeolite is treated with a stream of air at 1000 TF.

for at least 15 minutes The zeolite is then flushed with helium and the temperature adjusted to between 550 'F and 950 'F to give an overall conversion between 10 % and 60 %.

The mixture of hydrocarbons is passed at 1 liquid hourly space velocity (i e 1 volume of liquid hydrocarbon per volume of zeolite per hour) over the zeolite with a helium dilution 20 to give a helium to total hydrocarbon mole ratio of 4:1 After 20 minutes on stream, a sample of the effluent is taken and analyzed, most conveniently by gas chromatography, to determine the fraction remaining unchanged for each of the two hydrocarbons.

The "constraint index" is calculated as follows:

25 Constraint Index go (fraction of n-hexane remaining) rm j (fraction of 3-methylpentane remaining) The constraint index approximates the ratio of the cracking rate constants for the two 30 hydrocarbons Zeolites suitable for the present invention are those having a constraint index in the approximate range of 1 to 12 Constraint Index (CI) values for some typical zeolites are:

CAS C I 35 ZSM-5 8 3 ZSM-11 8 7 ZSM-12 2 ZSM-38 2 40 ZSM-35 45 TMA Offretite 3 7 Beta 0 6 ZSM-4 05 H-Zeolon 0 4 45 REY 0 4 Amorphous Silica-Alumina 0 6 Erionite 38 It is to be realized that the above constraint index values typically characterize the 50 specified zeolites but that such are the cumulative result of several variables used in determination and calculation thereof Thus, for a given zeolite depending on the temperature employed within the aforenoted range of 550 F to 950 F, with accompanying conversion between 10 % and 60 %, the constraint index may vary within the indicated approximate range of 1 to 12 Likewise, other variables such as the crystal size of the 55 zeolite, the presence of possible occluded contaminants and binders intimately combined with the zeolite may affect the constraint index It will accordingly be understood by those skilled in the art that the constraint index, as utilized herein, while affording a highly useful means for characterizing the zeolites of interest is approximate, taking into consideration the manner of its determination, with probability, in some instances, of compounding 60 variable extremes However, in all instances, at a temperature within the above-specified range of 550 F to 950 F, the constraint index will have a value for any given zeolite of interest herein within the approximate range of 1 to 12.

The class of zeolites defined herein is exemplified by ZSM-5, ZSM-11, ZSM12, ZSM-35, ZSM-38 and other similar materials U S Patent 3 702,886 describes and claims ZSM-5 65 1 587 298 ZSM-11 is more particularly described in U S Patent 3,709,979.

ZSM-12 is more particularly described in U S Patent 3,832,449.

ZSM-38 is more particularly described in U S Patent 4,046,859 This zeolite can be identified, in terms of mole ratios of oxides and in the anhydrous state, as follows:

5 ( 0.3-2 5)R 20: ( 0-0 8)M 20: A 1203: > 8 Si O 2 wherein R is an organic nitrogen-containing cation derived from a 2(hydroxyalkyl) trialkylammonium compound and M is an alkali metal cation, and is characterized by a specified X-ray powder diffraction pattern 10 In a preferred synthesized form, the zeolite has a formula, in terms of mole ratios of oxides and in the anhydrous state, as follows:

( 0.4-2 5)R 20: ( 0-0 6)M 20: A 1203: x Si O 2 15 wherein R is an organic nitrogen-containing cation derived from a 2(hydroxyalkyl) trialkylammonium compound, wherein alkyl is methyl, ethyl or a combination thereof, M is an alkali metal, especially sodium, and x is from greater than 8 to about 50.

The synthetic ZSM-38 zeolite possesses a definite distinguishing crystalline structure whose X-ray diffraction pattern shows substantially the significant lines set forth in Table I 20 It is observed that this X-ray diffraction pattern (significant lines) is similar to that of natural ferrierite with a notable exception being that natural ferrierite patterns exhibit a significant line at 11 33 A.

TABLE I 25 d (A) I/Io 9.8 0 20 Strong 9 1 0 19 Medium 30 8.0 0 16 Weak 7.1 + 0 14 Medium 6.7 0 14 Medium 6.0 0 12 Weak 6 0 0 12 Weak 35 4.37 + 0 09 Weak 4.23 + 0 09 Weak 4.01 + 0 08 Very Strong 3.81 + 0 08 Very Strong 3 69 0 07 Medium 40 3.57 0 07 Very Strong 3.51 0 07 Very Strong 3.34 0 07 Medium 3.17 0 06 Strong 3 08 + 0 06 Medium 45 3.00 + 0 06 Weak f 2 92 + 0 06 Medium 2.73 + 0 06 Weak 2.66 + 0 05 Weak 2 60 + 0 05 Weak 50 2.49 + 0 05 Weak A further characteristic of ZSM-38 is its sorptive capacity providing said zeolite to have increased capacity for 2-methylpentane (with respect to n-hexane sorption by the ratio n-hexane/2-methyl-pentane) when compared with a hydrogen form of natural ferrierite 55 resulting from calcination of an ammonium exchanged form The characteristic sorption ratio n-hexane/2-methylpentane for ZSM-38 (after calcination at 600 C) is less than 10, whereas that ratio for the natural ferrierite is substantially greater than 10, for example, as high as 34 or higher.

Zeolite ZSM-38 can be suitably prepared by preparing a solution containing sources of an 60 alkali metal oxide, preferably sodium oxide, an organic nitrogencontaining oxide, an oxide of aluminum, an oxide of silicon and water and having a composition, in terms of mole ratios of oxides, falling within the following ranges:

1 587 298 5 R+ Broad Preferred R+ + M+ 0 2-1 0 03-0 9 OH/Si O 2 0 05-0 5 0 07-0 49 H 20/OH 41-500 100-250 5 Si O 2/A 1203 8 8-200 12-60 wherein R is an organic nitrogen-containing cation derived from a 2(hydroxyalkyl) trialkylammonium compound and M is an alkali metal ion, and maintaining the mixture until crystals of the zeolite are formed (The quantity of OH is calculated only from the 10 inorganic sources of alkali without any organic base contribution) Thereafter, the crystals are separated from the liquid and recovered Typical reaction conditions consist of heating the foregoing reaction mixture to a temperature of from about 90 MC to about 400 C for a period of time of from about 6 hours to about 100 days A more preferred temperature range is from about 150 MC to about 400 C with the amount of time at a temperature in 15 such range being from about 6 hours to about 80 days.

The digestion of the gel particles is carried out until crystals form The solid product is separated from the reaction medium, as by cooling the whole to room temperature, filtering and water washing The crystalline product is thereafter dried, e g at 230 'F for from about 8 to 24 hours 20 ZSM-35 is more particularly described in U S Patent No 4,016,245 This zeolite can be identified, in terms of mole ratios of oxide and in the anhydrous state, as follows:

( 0.3-2 5)R 20: ( 0-0 8)M 20: A 1203: > 8 Si O 2 25 wherein R is an organic nitrogen-containing cation derived from ethylenediamine or pyrrolidine and M is an alkali metal cation, and is characterized by a specified X-ray powder diffraction pattern.

In a preferred synthesized from the zeolite has a formula, in terms of mole ratios of oxides and in the anhydrous state, as follows: 30 ( 0.4-2 5)R 20: ( 0 0 6)M 20: A 1203: x Si O 2 wherein R is an organic nitrogen-containing cation derived from ethylenediamine or pyrrolidine, M is an alkali metal, especially sodium, and x is from greater than 8 to about 35 50.

The synthetic ZSM-35 zeolite possesses a definite distinguishing crystalline structure whose X-ray diffraction pattern shows substantially the significant lines set forth in Table II.

It is observed that this X-ray diffraction pattern (with respect to significant lines) is similar to that of natural ferrierite with a notable exception being that natural ferrierite patterns 40 exhibit a significant line at 11 33 A Close examination of some individual samples of ZSM-35 may show a very weak line at 11 3-11 5 A This very weak line, however, is dtermined not to be a significant line for ZSM-35.

1 587 298 TABLE II

D (A) 9.6 + 0 27.10 + 6.98 + 6.64 + 5.78 + 5.68 + 4.97 + 4.58 + 3.99 + 3.94 + 3.85 + 3.78 + 3.74 + 3.66 + 3.54 + 3.48 + 3.39 + 3.32 + 3.14 + 2.90 + 2.85 + 2.71 + 2.65 + 2.62 + 2.58 + 2.54 + 2.48 + 0.15 0.14 0.14 0.12 0.12 0.10 0.09 0.08 0.08 0.08 0.08 0.08 0.07 0.07 0.07 0.07 0.07 0.06 0.06 0.06 0.05 0.05 0.05 0.05 0.05 0.05 I/Io Very StrongVery Very Strong Medium Medium Medium Weak Weak Weak Weak Strong Medium Strong Medium Strong Weak Medium Very Strong Very Strong Weak Weak Medium Weak Medium Weak Weak Weak Weak Weak Weak Weak Weak A further characteristic of ZSM-35 is its sorptive capacity proving said zeolite to have increased capacity for 2-methylpentane (with respect to n-hexane sorption by the ratio n-hexane/2-methylpentane) when compared with a hydrogen form of natural ferrierite resulting from calcination of an ammonium exchanged form The characteristic sorption ratio n-hexane/2-methylpentane for ZSM-35 (after calcination at 600 C) is less than 10, whereas that ratio for the natural ferrierite is substantially greater than 10, for example, as high as 34 or higher.

Zeolite ZSM-35 can be suitably prepared by preparing a solution containing sources of an alkali metal oxide, preferably sodium oxide, an organic nitrogencontaining oxide, an oxide of aluminum, an oxide of silicon and water and having a composition, in terms of mole ratios of oxides, falling within the following ranges:

R+ + M+ OH-/Si O 2 H 20/OFHSi O 2/A 1203 Broad 0.2-1 0 0.05-0 5 41-500 8.8-200 Preferred 0.3-0 9 0.07-0 49 100-250 12-60 wherein R is an organic nitrogen-containing cation derived from pyrrolidine or ethylenediamine and M is an alkali metal ion, and maintaining the mixture until crystals of the zeolite are formed (The quantity of OH is calculated only from the inorganic sources of alkali without any organic base contribution) Thereafter, the crystals are separated from the liquid and recovered Typical reaction conditions consist of heating the foregoing reaction mixture to a temperature of from about 90 C to about 400 C for a period of time of from about 6 hours to about 100 days A more preferred temperature range is from about 150 C to about 400 C with the amount of time at a temperature in such range being from about 6 hours to about 80 days.

The digestion of the gel particles is carried out until crystals form The solid product is separated from the reaction medium, as by cooling the whole to room temperature, filtering and water washing The crystalline product is dried, e g at 230 F, for from about 8 to 24 hours.

A.6 1 587 298 The specific zeolites described, when prepared in the presence of organic cations, are catalytically inactive, possibly because the intracrystalline free space is occupied by organic cations from the forming solution They may be activated by heating in an inert atmosphere at 1000 'F for one hour, for example, followed by base exchange with ammonium salts followed by calcination at 1000 'F in air The presence of organic cations in the forming 5 solution may not be absolutely essential to the formation of this type zeolite; however, the presence of these cations does appear to favor the formation of this special type of zeolite.

More generally, it is desirable to activate this type catalyst by base exchange with ammonium salts followed by calcination in air at about 1000 'F for from about 15 minutes to about 24 hours 10 Natural zeolites may sometimes be converted to this type zeolite catalyst by various activation procedures and other treatments such as base exchange, steaming, alumina extraction and calcination, in combinations Natural minerals which may be so treated include ferrierite, brewsterite, stilbite, dachiardite, epistilbite, heulandite, and clinoptilolite The preferred crystalline aluminosilicates are ZSM-5, ZSM-11, ZSM-12, ZSM-38 and 15 ZSM-35, with ZSM-5 particularly preferred.

In a preferred aspect of this invention, the zeolites hereof are selected as those having a crystal framework density, in the dry hydrogen form, of not substantially below about 1 6 grams per cubic centimeter It has been found that zeolites which satisfy all three of these criteria are most desired because they tend to maximize the production of gasoline boiling 20 range hydrocarbon products Therefore, the preferred zeolites of this invention are those having a constraint index as defined above of about 1 to about 12, a silica to alumina mole ratio of at least about 500 and a dried crystal density of not less than about 1 6 grams per cubic centimeter The dry density for known structures may be calculated from the number of silicon plus aluminum atoms per 1000 cubic Angstroms, as given, e g, on Page 19 of the 25 article on Zeolite Structure by W M Meier This paper is included in "Proceedings of the Conference on Molecular Sieves, London, April 1967," published by the Society of Chemical Industry, London, 1968 When the crystal structure is unknown, the crystal framework density may be determined by classical pyknometer techniques For example, it may be determined by immersing the dry hydrogen form of the zeolite in an organic solvent 30 which is not sorbed by the crystal It is possible that the unusual sustained activity and stability of this class of zeolites is associated with its high crystal anionic framework density of not less than about 1 6 grams per cubic centimeter This high density, of course, must be associated with a relatively small amount of free space within the crystal, which might be expected to result in more stable structures This free space, however, is important as the 35 locus of catalytic activity.

Crystal framework densities of some typical zeolites are:

Void Framework Zeolite Volume Density 40 Ferrierite 0 28 cc/cc 1 76 g/cc Mordenite 28 17 ZSM-5, -11 29 1 79 Dachiardite 32 1 72 45 L 32 1 61 Clinoptilolite 34 1 71 Laumontite 34 1 77 ZSM-4 (Omega) 38 1 65 Heulandite 39 1 69 50 p 41 1 57 Offretite 40 1 55 Levynite 40 1 54 Erionite 35 1 51 Gmelinite 44 1 46 55 Chabazite 47 1 45 A 5 1 3 Y 48 1 27 When synthesized in the alkali metal form, the zeolite is conveniently converted to the 60 hydrogen form, generally by intermediate formation of the ammonium form as a result of ammonium ion exchange and calcination of the ammonium form to yield the hydrogen form In addition to the hydrogen form, other forms of the zeolite wherein the original alkali metal has been reduced to less than about 1 5 percent by weight may be used Thus, the original alkali metal of the zeolite may be replaced by ion exchange with other suitable 65 1 587 298 ions of Groups IB to VIII of the Periodic Table, including, by way of example, nickel, copper, zinc, palladium, calcium or rare earth metals.

In practicing the desired conversion process, it may be desirable to incorporate the above described crystalline aluminosilicate zeolite in another material resistant to the temperature and other conditions employed in the process Such matrix materials include synthetic or 5 naturally occurring substances as well as inorganic materials such as clay, silica and/or metal oxides The latter may be either naturally occurring or in the form of gelatinous precipitates or gels including mixtures of silica and metal oxides Naturally occurring clays which can be composited with the zeolite include those of the montmorillonite and kaolin families, which families include the sub-bentonites and the kaoins commonly known as Dixie, McNamee 10 Georgia and Florida clays or others in which the main mineral constituent is halloysite, kaolinite, dickite, nacrite or anauxite Such clays can be used in the raw state as originally mined or initially subjected to calcination, acid treatment or chemical modification.

In addition to the foregoing materials, the zeolites employed herein may be composited with a porous matrix material, such as alumina, silica-alumina, silicamagnesia, silica 15 zirconia, silica-thoria, silica-beryllia, silica-titania as well as ternary compositions, such as silica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesia and silica-magnesiazirconia The matrix may be in the form of a cogel The relative proportions of zeolite component and inorganic oxide gel matrix may vary widely with the zeolite content ranging from between about 1 to about 99 percent by weight and more usually in the range of about 20 to about 80 percent by weight of the composite.

The zeolites employed herein may also be physically mixed or diluted with particle-form solid of either an appropriate catalytic nature or substantially devoid of catalytic activity.

Typical of the latter are silica particles such as low surface area quartz chips.

The conversion process described herein may be carried out as a batch type, 25 semi-continuous or continuous operation utilizing a fixed or moving bed catalyst system.

The catalyst after use in a moving bed reactor is conducted to a regeneration zone wherein coke is burned from the catalyst in an oxygen-containing atmosphere, e g air, at an elevated temperature, after which the regenerated catalyst is recycled to the conversion zone for further contact with the charge stock In a fixed bed reactor, regeneration is 30 carried out in a conventional manner where an inert gas containing a small amount of oxygen ( 0 5-2 %) is used to burn the coke in a controlled manner so as to limit thetemperature to a maximum of around 500-550 'C.

The following examples will serve to illustrate the process of the invention without limiting the same: 35 Example 1

ZSM-5 characterized by a high silica/alumina mole ratio was prepared as follows:

I Prereacted Organics Preparation 40 The following materials were charged to a 30 gallon autoclave; 16,524 grams of methylethyl ketone, 10,008 grams of tri-n-propylamine and 8604 grams of npropyl bromide The contents were mixed with gentle agitation for 15 minutes The agitation was stopped and 123 Ibs of water were charged to the autoclave The autoclave was sealed and heated to 220 F and held at 220 F for 15 hours After this reaction period, the temperature 45 was raised to 320 F and the unreacted organics were flashed off The aqueous phase was removed containing the prereacted organics and contained 1 44 % wt nitrogen.

II Zeolite Synthesis a) Solution Preparation 50 Silicate Solution 90.9 lb Q-brand sodium silicate 52.6 lb H 20 118 g Daxad 27 (sodium salt of polymerized substituted benzenoid alkyl sulfonic acid 55 combined with a suspending agent "Daxad" is a registered Trade Mark) Acid solution 4138 g H 2504 1840 g Na CI 60 50.7 g Prereacted organics 14.7 lb H 20 Additional Solids 5890 g Na CI 65 1 587 298 Additional Liquid 1180 g H 20 b) Procedure The silicate solution and acid solution were mixed in a mixing nozzle to form a gel which 5 was discharged into a 30 gallon autoclave to which 1180 grams of water had been previously added The gel was whipped by agitation and 5890 grams of Na CI were added and thoroughly blended The autoclave was sealed and heated to -220 'F with agitation at 90 rpm and held for 54 3 hours until crystallization was completed The contents of the autoclave were cooled and discharged The crystallized product was analyzed by x-ray 10 diffraction and was found to be 100 % wt ZSM-5 The chemical analysis of the thoroughly washed crystalline product was:

% Wt Mole Ratio 15 A 1203 0 10 1 0 Si O 2 98 3 1670 Na 1 6 Na 2 O 35 5 N 0 75 63 9 20 C 8 98 892 Example 2

ZSM-5 having a silica/alumina mole ratio of about 70 was prepared as follows:

1874 pounds of tri-n-propylamine were mixed with 1610 lbs of n-propyl bromide, 3100 25 pounds of methyl ethyl ketone and 1254 gallons of deionized water The mixture was reacted at 210-218 'F, 5 RPM for 14 hours in an autoclave equipped with high shear agitation The resulting aqueous phase was designated Solution A.

586 gallons of deionized water were mixed with enough Q-brand sodium silicate to give a solution with a specific gravity of 1 222 24 pounds of Daxad 27 were added to the solution 30 The resulting solution was designated Solution B. 305 pounds of commercial grade aluminum sulfate ( 17 2 % A 1203) were dissolved in 437 gallons of deionized water To this solution, 733 pounds of sulfuric acid ( 93 2 wt % H 2504), 377 pounds of commercial grade Na CI and 1915 pounds of Solution A were added.

The resulting solution was designated Solution C 35 gallons of deionized water were added to an autoclave equipped with high shear agitation Solution B and Solution C were mixed simultaneously in a nozzle and sprayed into the autoclave 1200 pounds of commercial grade Na CI were added to the autoclave.

The resulting gel was mixed in the autoclave at 90 rpm and ambient temperature for 4 hours The gel was then reacted at 206-2260 F and 90 rpm for 40 hours and at 320 'F and 90 40 rpm for 3 hours The solid product was analyzed by x-ray diffraction and found to be ZSM-5 The solid product was washed by decantation with deionized water and 3500 ppm Primafloc C-7 (polyammonium bisulfate) until the sodium content of the product was less than 1 % The solid product was filtered on a rotary drum filter The resulting filter cake was dried at 310 F 45 The chemical analysis of the dried product was:

% Wt Mole Ratio A 1203 2 39 1 0 50 Si O 2 97 0 68 9 Na 0 96 Na 2 O 89 N 0 85 2 59 C 7 98 28 4 55 3.4 pounds of the dried product were calcined in N 2 for 3 hours at 1000 F.

1329 grams of the calcined product were mixed with 6645 cc of 1 N NH 4 NO 3 solution for 1 hour at ambient temperature The mixture was vacuum filtered The ion exchange procedure was repeated and the final filter cake was dried at 250 F The sodium content of 60 the final product was less than 0 05 % wt.

Examples 3-6

Using the catalysts of Examples 1 and 2, toluene was alkylated with ethylene Runs were made at atmospheric pressure over approximately 20 hour periods The catalysts were 65 TABLE III

A Catalyst of Example 1 (Si O 2/A 1203 = 1600/1) WHSV Temp To HV Tol.

Ex C C H 3 350 4 400 3.5 3.5 % Para CONVERSION, % in EthylToluene C 2 H 4 Toluene 17.1-12 70-54 31-33 20.4-17 4 86-78 29-30 B Catalyst of Example 2 (Si O 2/A 1203 = 70/1) WHSV Temp Tol.

Ex 'C C 2 H 4 350 6 400 6.9 6.5 % Para CONVERSION, % in EthylToluene C 2 H 4 Toluene 20.4-19 4 93-96 27 19.6-19 7 91-98 27 Para EthylToluene 30.1-32 2 28.3-29 9 Para EthylToluene 23.8-24 1 19.8-21 9 SELECTIVITY Meta EthylToluene TO PRODUCTS, wt % Ortho Ethyl Light Toluene Gases 64.7-64 5 1 9-1 3 66.6-66 7 SELECTIVITY Meta EthylToluene 53.9-55 1 43.1-48 3 4.2-3 1 4- 1 TO PRODUCTS, wt % Ortho Ethyl Light Toluene Gases 11.1-9 9 6-1 4 10.4-11 2 4 4-2 1 Light gases are composed of methane, ethane, propane, propylene, C 4 paraffins and C 4 olefins.

Other aromatics include benzene, ethylbenzene, xylenes and diethylbenzene.

Uc t'.) \ O Ct, o Other Aromatics -' 3.1-1 9 5- 2 = ,, Pl U) g, Other Aromatics 10.6-9 5 c 5 C,-c > CDP 22.3-16 5 C D CD CD cr er cl CD _:

Cp D (t pt, 11 1 587 298 11 It will be seen from the above comparative data that the use of high Si O 2/A 1203 ZSM-5 catalyst, typified by the catalyst of Example 1, effected a very substantial reduction in undesired by-product formation.

A comparison of the selectivity to side reaction products is summarized in Table IV below 5 O P 4 e V o o p Cci 0 _ k LIEH N _ ocnC ó O 00 t Ho u _) Cl _ E o I o 12 1 587 298 12 It will be evident that at a reaction temperature of 350 C, 3-7 fold reductions in undesired by-products were observed using the zeolite catalyst of high Si O 2/A 1203 ratio and that at 400 C substantially higher by-product reductions of 11-21 fold for light gas formation and 45-83 fold for other aromatics production were observed.

5 Examples 7-9

In a manner similar to that described in Examples 3-6 utilizing the catalysts described in Examples 1 and 2, alkylation of ethylbenzene with ethylene was effected The conditions of reaction and analytical results are summarized in Table V below.

c c 5, 3 3 O O P 4 P 4 EH, H, O C C C >-. Cw N cq > x> c H a H a C' C ,e; " t C À ' c ot CZNC _> 7, O O Cc O Cn CV)/ I Z _C C ^ N X > t > , N Z O r c c, c c C L C) C > O 2 Xc 0; t m; X U i 1 N C 13 1 587 298 13 It will be seen from the above data that selectivity to the desired diethylbenzene product was substantially greater utilizing the catalyst of higher silica/alumina ratio ( 1600/1) and that formation of by-product gases and other aromatic compounds was relatively low.

The catalyst of lower sislica/alumina ratio ( 70/1) was much more active as indicated by the high conversion of ethylbenzene at 350 C Moreover, even when the temperature was 5 lowered to 250 C to reduce conversion, relatively large amounts of byproducts were produced as compared with those obtained utilizing the catalyst of higher silica/alumina ratio.

Claims (1)

1. WHAT WE CLAIM IS:-

   1 A process for effecting ethylation of a monoalkyl benzene wherein the alkyl 10 substituent contains 1 or 2 carbon atoms to yield a mixture of ethyl toluene or diethylbenzene isomers with minimal undesired by-product formation, which comprises contacting said monoalkyl benzene with an ethylating agent, under conversion conditions, including a temperature between about 250 C and about 600 C, a pressure between about 0 1 and about 100 atmospheres, utilizing a feed weight hourly space velocity between about 15 0.1 and about 1000, in the presence of a catalyst comprising a crystalline aluminosilicate zeolite characterized by a constraint index within the approximate range of 1 to 12 and a silica to alumina mole ratio of at least about 500.

   2 The process as claimed in Claim 1 wherein the molar feed ratio of monoalkyl benzene/ethylating agent is between about 1 and about 10 20 3 The process as claimed in Claim 1 or 2, wherein said mono alkyl benzene is toluene.

   4 The process as claimed in Claim 1 or 2, wherein said mono alkyl benzene is ethylbenzene.

   The process as claimed in any one of Claims 1 to 4, wherein said ethylating agent is ethylene, ethyl alcohol, ethyl halide, diethyl ether, ethyl mercaptan or diethyl sulfide 25 6 The process as claimed in Claim 5 wherein said ethylating agent is ethylene.

   7 The process as claimed in any one of Claims 1 to 6 wherein said crystalline aluminosilicate zeolite is ZSM-5.

   8 The process as claimed in any one of the preceding Claims wherein said crystalline aluminosilicate is admixed with a diluent or a binder therefor 30 9 The process as claimed in any one of the preceding Claims wherein said crystalline aluminosilicate zeolite is characterized by a silica to alumina mole ratio greater than about 500 but not exceeding about 2000.

   The process as claimed in Claim 9 wherein said crystalline aluminosilicate zeolite is characterized by a silica to alumina mole ratio greater than about 1000 but not exceeding 35 about 2000.

   11 A process for ethylating a mono alkyl benzene according to Claim 1 substantially as described herein with reference to the foregoing Examples.

   12 The ethylated product of the process of any one of the preceding claims.

   40 For the Applicants, CARPMAELS & RANSFORD, Chartered Patent Agents, 43 Bloomsbury Square, London WC 1 A 2 RA 45 Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey 1981.

   Published by The Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.